Acknowledgements

This web book is the result of work of my colleagues:

• Enrico Pegoraro, who wrote all versions of this book
• Veronica Giro, who reviewed and reassembled all these materials.

However, it would not have been possible without the sharing of knowledge, information, ideas, doubts and even criticisms of many individuals on the internet. I would like to extend my sincere thanks to all of them.

Andrea Spanò,
Quantide s.r.l.